In the operation of a gas laser such as, for example, an argon or krypton gas laser, it is common to utilize an electrically induced magnetic field to increase the beam density in the active medium for more efficient excitation. An elongate electromagnetic solenoid, optionally assembled from a series of shorter solenoids, connected to a power source surrounds the laser tube and is used for this purpose. During operation of the solenoid, the electric current passing through the solenoid will generate a significant amount of heat which contributes to the overall heat generated by other components of the laser and which, in the vicinity of the solenoid, may get as high as 250.degree. C.
One known approach to correct for the heat build up in and around a gas laser tube and any solenoid component is to add means for artificial cooling, utilizing either air or water circulation. Such cooling means is of some help, but has a limitation in the amount of heat that can be removed.
The solenoid itself has typically been constructed with an epoxy resin encapsulation to physically and electrically protect the windings of the coil. This epoxy resin has fairly good electrical insulation properties, good mechanical properties, and moderate thermal tolerance. However, epoxy encapsulating resin, when fully cured, only has a temperature resistance of up to 130.degree. C. Beyond this temperature, the epoxy resin will break down, melt and burn, thereby degrading and destroying its electrically insulative and mechanically protective value. Since hot air surrounding the tube or flowing in an air cooling system may exceed 130.degree. C. in temperature, the epoxy resin tends to degrade when exposed to such extremely hot air, subjecting the solenoid to electrical failure.
Therefore, an objective of the present invention is to provide a gas laser solenoid which will withstand a high temperature environment.
An additional objective of the invention is to provide a gas laser solenoid capable of operating at a higher temperature than that which will degrade cured epoxy resin.
A further objective of the invention is to provide a improved cooling means for a solenoid in a gas laser.
These and further objectives will become apparent to those skilled in the art from the description which follows.